Synthesis, spectral characterization, theoretical, antimicrobial, DNA interaction and in vitro anticancer studies of Cu(II) and Zn(II) complexes with pyrimidine-morpholine based Schiff base ligand

Novel Cu(II) (1) and Zn(II) (2) complexes with 4-(1-(4-morpholinophenyl)ethylideneamino)pyrimidine-5-carbonitrile) (L) have been synthesized and characterized by various spectroscopic and analytical techniques. DFT (density functional theory) studies result confirms that, LMCT mechanism have been done between L and M(II) ions. The antimicrobial studies indicate that the ligand L and complexes 1 &2 exhibit higher activity against the E. coli bacteria and C. albicans fungi. The groove binding mode of ligand L and complexes 1 &2 with CT-DNA have been confirmed by electronic absorption, competitive binding, viscometric and cyclic voltammetric studies. The electronic absorption titration of ligand L and complexes 1 &2 with DNA have been carried out in different buffer solutions (pH 4.0, 7.0 & 10.0). The Kb values of ligand L and complexes 1 &2 are higher in acidic buffer at pH 4.0 (Kb=2.42×105, L; 2.8×105, 1; 2.65×105, 2) and the results revealed that, the interaction of synthesized compounds with DNA were higher in the acidic medium than basic and neutral medium. Furthermore, CT-DNA cleavage studies of ligand L and complexes 1 &2 have been studied. The in vitro anticancer activities results show that complexes 1 &2 have moderate cytotoxicity against cancer cell lines and low toxicity on normal cell line than ligand L.